Cameras are commonly used for monitoring purposes. For example, cameras may be arranged to monitor premises or vehicles. As the cameras degrade or get out of order, maintenance staff is sent out to repair or replace the cameras. Typically, a monitoring camera is arranged at a remote location and it is therefore costly to send out maintenance staff to perform service work on the cameras.
In order to mitigate this problem, the cameras may perform self-tests such that the cameras themselves may detect if there is a fault which needs to be attended to. If a camera detects that there is fault, maintenance staff may be notified and can take necessary action to repair or replace the camera.
There are different ways of performing self-tests. US2007126869 A1 discloses an automatic camera health monitoring which measures the health of a camera by comparing a current image to a set of stored images. The camera detects a fault if the measured health exceeds a threshold.
A drawback of the known self-tests is that they may give an unreliable result. As a consequence, maintenance staff may be sent out to repair the cameras in vain.